ML20066F412

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Discusses Corrective Actions & Insp Subsequent to C Reactor Coolant Pump Seal Failure.Account of Event Which Caused Occurrence Included
ML20066F412
Person / Time
Site: Robinson Duke Energy icon.png
Issue date: 07/28/1975
From:
CAROLINA POWER & LIGHT CO.
To: Moseley N
NRC OFFICE OF INSPECTION & ENFORCEMENT (IE REGION II)
Shared Package
ML20066F411 List:
References
FOIA-82-433 NG-75-1139, NUDOCS 8211180268
Download: ML20066F412 (1)


Text

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Carchna Power & tight Company ,

July 28, 1975 File: NG-3513 (R) Serial: NG-75-1139 Mr. Norman C. Moscit y, Director '

U. S. .'iucicar Regulatory Commission _

Region II, Suite 81f 230 Peachtree Street, N.W.

Atlanta, Georgia 20303 .

\

Dear Fr. Mor.eley:

H. B. ROBINSON UNIT No. 2 -_ -

LICENSE NO. DPR-23 CORRECTIVE ACTIONS AND INSPECTIONS SUBSEQUENT TO "C" REACTOR COOLANT PUMP SEAL FAILURE In response to an informal request by a member of your staff, the following summary of actions taken following Abnornal Occurrence 50-261/75-9 is previded f or your inf orr..ation. Included are summaries of repairs and .

inspec tions perf ortred dering the forced outage in order to return the plant te s::f e ope ~ation.

Tie event which caused this outage was the failure of "C" reactor coolant pum- (RCP) scal:, and subsequent flooding of the containment lower level. Thi- was report d via Abnornal Occurrence Report 50-261/75-9. An account of ;his occurrence is included below.

O i Thursday, i:ay 1,1975, the plant was operating normally at 100% l power havin; just ecmpleted a two-week maintenance outage. At about 1700 the seal ]cak-o f flow on RrP "C" began to oscillate a bit. At 1811 the seal leak-c,f f flow f ailed hir.h, indicating a f ailed No. 1 seal. The plant was l reduced to 38% power at 10% per minute by control of the turbine (can operate at 40; on two loops), nt 1818 PCP "C" was stopped. At 1819 Reactor Trip No. 192 ocentred due to " Turbine Trip" caused by high steam generator level.

At 1832 RCP's "/" and " ;" were stopped when the Cocponent Cooling Return Valve f rom t he RC s (CCW-626' shut on high flow and would not stay open.

Later this

C" p rovec: to b. a result o ' flashing of the component cooling water in RCP therral bar rier cooling coils which caused surges on the return line and on flown: ter F [d-626 (0-15') gpm) which shuts CCW-626 on high flow. There was not ~

contiinous high flow in this line, no increase in component cooling surge tank 3evel as noted, and radiation monitor R-17 showed no increase. For these reasons the integrity of RCP "C" thereal barrier cooling coils was concluded to be intact. A high standpipe level on RCP "A" was also received at this titre. There wa. concern that seal flow would be lost on RCP's "A" and "b" since there was fla hing and high temperature (300*F) on the scal water return line for these pucps, thus the puups were secured.

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